It has previously been proposed to test a plurality of electrical components by clamping connecting leads from the components in test apparatus which can also be introduced into controlled environments, for example of high heat, humidity, or the like, or high electrical stresses, such as excess voltage and the like, in order to burn in the components and test them after having been exposed, for example, to stressful conditions which may well exceed the normal operating conditions under which they are intended to be used. The test elements are, for example, simultaneously subjected to thermal and electrical stress. In a burn-in apparatus, a predetermined temperature is generated by a hot-air current, for example of up to about 200.degree., which is maintained for example as a flow of air stream. Simultaneously, the test elements are subjected to electrical voltages, for example to test their operating reliability, insulation capacity, and the like. German Utility Model 83 04 116 describes a test chamber of this type, in which strip-like holding elements are placed into a chamber, the strip-like holding elements retaining the test samples. The outside of the chamber includes electrical connection elements to apply voltage to the test elements.